Check this link out it may help.
I struggle with these.

Try changing the LIKE to =

Hi Katie,

Thanks for using Community Hub.

Currently that expression says if the file is blank show serial numbers whereas your opening line says to show that if it is populated?

Also, is it if all of them are blank or just one as that would affect the logic?

Regards,

Andy

SALES_ORDER.NOTES_1 = "" OR SALES_ORDER.NOTES_2 = "" OR SALES_ORDER.NOTES_3 = "" ? " Serial Numbers " : ""

That should do what you need I think

it is still bringing up serial numbers when the field is not populated. 

if all are blank to now show serial numbers 

Sorry I had that the wrong way around. Should be

SALES_ORDER.NOTES_1 = "" OR SALES_ORDER.NOTES_2 = "" OR SALES_ORDER.NOTES_3 = "" ? "" : " Serial Numbers "

Or if you also need to deal with nulls:

SALES_ORDER.NOTES_1 = "" OR SALES_ORDER.NOTES_1 = null OR SALES_ORDER.NOTES_2 = "" OR SALES_ORDER.NOTES_2 = null OR SALES_ORDER.NOTES_3 = "" OR SALES_ORDER.NOTES31 = null ? "" : " Serial Numbers "

You only want serial numbers to show when all of them are blank rather than just any one of them is blank?

no i want serial number to show when wither note 1,2 or 3 has something in, then do not show serial number when all 3 are blank 

(SALES_ORDER.NOTES_1 <> "" AND SALES_ORDER.NOTES_1 <> null) OR (SALES_ORDER.NOTES_2 <> "" AND SALES_ORDER.NOTES_2 <> null) OR (SALES_ORDER.NOTES_3 <> "" AND SALES_ORDER.NOTES_3 <> null) ? " Serial Numbers " : ""

you are amazing , thankyou so very much